Sliding sleeves are used as downhole valves. They are frequently disposed in a recess in a tubular that defines opposed travel stops that coincide with two positions for the valve. The sleeve typically has a recess at opposed ends so that a known shifting tool can grab it and move the sleeve between stops. The surrounding tubular can have a port and the sleeve can have a second port. When the sleeve is against one stop the port in the tubular can be obstructed. When the sleeve is at the opposite stop, the sleeve port aligns with the tubular port for the open position.
Recently, designs have developed that require a valve member like a sleeve to be in more than two positions defined by its travel stops. In one such application a tubular port needs to be closed in one position, fully open in another and in a third position for alignment of a filter media with the port. In the open position a surrounding formation can be fractured with minimal flow resistance at the wide open port. In the third position, the formation fluids can be produced through the same tubing port with a sand control material in the flow path. In one such design, the sliding sleeve has two ports with one port containing the screen material. A design of this type is shown in PCT/US2005/011869. The problem arises in how the surface personnel can know when the sleeve has obtained an interim position between its travel stops.
One way this has been addressed in the past is to mount the sleeve on a j-slot and move it mechanically or hydraulically through the pattern in the j-slot to define any number of desired positions. This design adds complexity and cost in that in the hydraulic version a ball has to catch on a seat and pressure is cycled a given number of times to get the right position. After that the ball and seat need to get blown out so other procedures further downhole can take place. The drift diameter through the tool is reduced to make room for the pin in slot arrangement.
Another way to do this is using a control line to move a piston that is linked to the sleeve. A finite amount of hydraulic fluid is pumped that corresponds to a given displacement of the piston. However this method has uncertainties relating to the amount of fluid pumped being a small quantity through a long control line which can be subject to thermal effects or even a compressible gas bubble that can through off the amount of the intended movement. Additionally, the drag force of seals or the momentum of the hydraulic piston can also result in a different amount of movement than intended.
The present invention provides a tool and a method for shifting a sleeve to an interim position or positions between travel stops and giving feedback to the surface that the required amount of movement has taken place. In the event of a failure to release an emergency release option is available. The tool resets after a normal release and can be re-engaged if desired. The tool is operable in either direction depending on how its component parts are oriented. These and other details of the present invention will be more readily understood by those skilled in the art from a review of the description of the preferred embodiment and the associated drawings that appear below with the understanding that the appended claims represent the full scope of the invention.